The invention relates in general to wireless telecommunications networks and related applications and, in particular, to a method and system of assigning frequencies from a reuse group according to service type and subscriber location in a wireless communications network utilizing multiple reuse frequency groups for the assignment of transmission channels.
Without limiting the scope of the invention, its background is described in connection with assigning frequencies from a reuse group according to service type and subscriber location, as an example.
Wireless communication technology has experienced unprecedented growth, fueled by advances in radio frequency, satellite, and microelectronic technologies, and by the convenience of access to telephony and portable wireless devices. Several technologies have emerged for providing wireless communications, including analog systems such as Advanced Mobile Phone System (AMPS), and digital systems such as Global System for Mobile Communications (GSM) and Digital AMPS (D-AMPS). Cellular radio systems operate in an interference-limited environment and typically rely on frequency reuse plans to maximize capacity and quality. Protocols such as Frequency Division Multiple Access (FDMA), in analog systems, and Time Division Multiple Access (TDMA), in digital systems, for example, are used for this purpose.
In packet data systems, however, the throughput is dependent on the Carrier-to-Interference (C/I) ratio in both CDMA and TDMA systems. That is, speech quality is measurable as a function of the Carrier-to-Interference (C/I) ratio as well as the Bit Error Rate (BER). In Generalized Packet Radio Services (GPRS) and EDGE systems, multiple coding and/or modulation schemes that provide a different throughput for different C/Is are used. Such schemes provide different degrees of link robustness that are inversely proportional to the throughput. In general, however, packet data users do not all have the same throughput requirements since different applications are in use, ranging from digital voice to high rate data transmissions. At the same, the throughput realized by a particular user depends largely on the user""s position from the base station and hence C/I.
The network is designed to support multiple reuse patterns wherein frequency groups are created and reuse of the frequencies in a particular area is dictated in terms of cell distance. Consideration of the reuse pattern as a function of service quality has not, until the present invention, been contemplated. Therefore, a means of assigning frequencies from a frequency reuse group according to service type and subscriber location in the network would be advantageous.
The present invention provides a method and system of assigning frequencies from a reuse group according to service type and subscriber location in a wireless communications network utilizing multiple reuse frequency groups for the assignment of transmission channels.
Accordingly, disclosed in one embodiment is a method of assigning frequencies from a reuse group according to service type and subscriber location in a wireless communications network utilizing multiple reuse frequency groups or xe2x80x9cpatternsxe2x80x9d for the assignment of transmission channels. The method comprises the step of a mobile station in the network requesting a transmission channel. Next, the request is received and the data rate requirements of the mobile station for the level of service provided by the network to the mobile station are determined. Concurrently, the signal strength from the mobile station to a serving base station subsystem is measured.
The method further comprises the step of assigning a frequency to the mobile station, where the frequency is one belonging to a reuse frequency group that supports the data rate requirements at the measured signal strength. In assigning frequencies, and according to one embodiment of the invention, frequencies from a low frequency reuse group are assigned to a mobile station user with low data rate requirements. Likewise, frequencies from a high frequency reuse group are assigned to a mobile station user with high data rate services requirements.
Distance from the base station subsystem that serves the mobile station may also be used in determining the frequency reuse group to select in assigning frequencies. As such, frequencies from a low frequency reuse group may be assigned to a high data rate user which is close in distance to the base station subsystem; or frequencies from a high frequency reuse group may be assigned to a low data rate user which is far in distance to the base station subsystem.
Technical advantages of the present invention include more efficient use of network resources as users with low data rate service requirements are assigned frequencies that support their needs, while high data rate users are assigned frequencies from high frequency reuse groups.